<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <button v-on:click="sayHi">点这里</button>
        <button @click="sayHi">点这里</button>
    </div>
</body>
<script src="https://cdn.jsdelivr.net/npm/vue@2.5.21/dist/vue.js"></script>
<script>
    var vm = new Vue({
        el:'#app',
        data () {
            return {
                message:'helloword!'
            }
        },
            methods:{
                sayHi:function (event){
                    alert(this.message);
                }
        }
    });
</script>
</html>